Backends: Vulkan: fixed texture synchronization. (#8772)

backends/imgui_impl_vulkan.cpp

@@ -27,6 +27,7 @@
 
 // CHANGELOG
 // (minor and older changes stripped away, please see git history for details)
+//  2025-07-07: Vulkan: Fixed texture synchronization issue introduced on 2025-06-11. (#8772)
 //  2025-06-27: Vulkan: Fixed validation errors during texture upload/update by aligning upload size to 'nonCoherentAtomSize'. (#8743, #8744)
 //  2025-06-11: Vulkan: Added support for ImGuiBackendFlags_RendererHasTextures, for dynamic font atlas. Removed ImGui_ImplVulkan_CreateFontsTexture() and ImGui_ImplVulkan_DestroyFontsTexture().
 //  2025-05-07: Vulkan: Fixed validation errors during window detach in multi-viewport mode. (#8600, #8176)
@@ -808,6 +809,7 @@ void ImGui_ImplVulkan_UpdateTexture(ImTextureData* tex)
         {
             VkImageMemoryBarrier copy_barrier[1] = {};
             copy_barrier[0].sType = VK_STRUCTURE_TYPE_IMAGE_MEMORY_BARRIER;
+            copy_barrier[0].srcAccessMask = VK_ACCESS_HOST_WRITE_BIT;
             copy_barrier[0].dstAccessMask = VK_ACCESS_TRANSFER_WRITE_BIT;
             copy_barrier[0].oldLayout = VK_IMAGE_LAYOUT_UNDEFINED;
             copy_barrier[0].newLayout = VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL;
@@ -817,7 +819,7 @@ void ImGui_ImplVulkan_UpdateTexture(ImTextureData* tex)
             copy_barrier[0].subresourceRange.aspectMask = VK_IMAGE_ASPECT_COLOR_BIT;
             copy_barrier[0].subresourceRange.levelCount = 1;
             copy_barrier[0].subresourceRange.layerCount = 1;
-            vkCmdPipelineBarrier(bd->TexCommandBuffer, VK_PIPELINE_STAGE_HOST_BIT, VK_PIPELINE_STAGE_TRANSFER_BIT, 0, 0, nullptr, 0, nullptr, 1, copy_barrier);
+            vkCmdPipelineBarrier(bd->TexCommandBuffer, VK_PIPELINE_STAGE_FRAGMENT_SHADER_BIT | VK_PIPELINE_STAGE_HOST_BIT, VK_PIPELINE_STAGE_TRANSFER_BIT, 0, 0, nullptr, 0, nullptr, 1, copy_barrier);
 
             VkBufferImageCopy region = {};
             region.imageSubresource.aspectMask = VK_IMAGE_ASPECT_COLOR_BIT;